Description
Why It’s Done:
This test is performed to:
• Classify the type of breast cancer based on hormone receptor status (ER/PR).
• Guide hormone therapy decisions — cancers that are ER/PR positive often respond well to hormone-blocking treatments.
• Monitor cancer recurrence or metastasis using CA 15-3, especially in advanced stages.
• Evaluate treatment effectiveness in patients undergoing therapy for breast cancer.
CA 15-3 is not used for initial diagnosis but is valuable in tracking the course of the disease over time.
Preparation:
• For ER/PR Testing: Requires a tissue sample from a biopsy or surgical specimen. No special patient preparation is needed.
• For CA 15-3 Testing: A blood sample is required. Minimal preparation is needed, but your healthcare provider may recommend:
o Fasting for a few hours (optional, depending on lab protocol)
o Informing them of any medications or supplements being taken
